Al Molinaro, the basset-hound-faced character actor who was known for playing Al Delvecchio, the harried diner owner on the long-running sitcom “Happy Days” — and who recommended a little-known comic named Robin Williams to portray an alien named Mork on a 1978 episode of the show — died on Friday in Glendale, Calif. He was 96.

His son, Michael Molinaro,confirmed the death.

A big, bluff man with soulful eyes and a vast, wayward nose that seemed to meander in several directions at once, Mr. Molinaro appeared born to play comedy. He was a regular cast member in Seasons 4 through 9 of “Happy Days,” which was broadcast on ABC from 1974 to 1984; left the show to reprise his role in a short-lived spinoff, “Joanie Loves Chachi” (1982-83); and reappeared on “Happy Days” toward the end of its run.

Set in midcentury Milwaukee, “Happy Days” followed the fortunes of a group of teenagers, chief among them Richie Cunningham (played by Ron Howard) and Arthur Fonzarelli (Henry Winkler), familiarly known as the Fonz.

His character, who ran the beanery — originally known as Arnold’s and later called Al’s — where the group congregated, was known for the catchphrase “Yup-yup-yup-yup,” uttered in a world-weary phonetic blur.

He had previously played the hapless policeman Murray Greshler on “The Odd Couple,” starring Tony Randall and Jack Klugman, broadcast on ABC from 1970 to 1975. In later years Mr. Molinaro was a seen in a spate of television commercials, including spots for Mr. Big toilet paper and On-Cor frozen dinners.

Michael Molinaro said that his father had a special affection for New York City, the setting for “The Odd Couple,” and that he lived there for a time in a Midtown hotel as he sought work in commercials.

“The first time I went to New York City it was because he had moved there to do a number of commercials,” the younger Mr. Molinaro said in a phone interview on Friday. “He did not merely play a cop walking the beat on ‘The Odd Couple.’ He used to walk the streets of New York City and loved it.”

The son of Rafaele and Teresa Molinaro, immigrants from Italy, Albert Francis Molinaro was born on June 24, 1919, in Kenosha, Wis. In high school, from which he took an extra year to graduate, he was barred from extracurricular activities like drama that might have compromised his studies.

“It was my fault, not the teachers’,” Mr. Molinaro told The Associated Press in 1980. “I had an iron skull and they were trying to pound something through it.”

In the early 1950s, Mr. Molinaro boarded a bus for Southern California. There he became financially secure through real estate speculation, which allowed him to try to make it in Hollywood. He studied acting, landing guest roles in the ’60s and ’70s on sitcoms like “Get Smart,” “Green Acres,” “That Girl” and “Bewitched.”

“I spent 20 years here before I got anything going,” Mr. Molinaro told The Kenosha News in 2004, speaking from his home in Glendale, Calif.

Then, through Penny Marshall, a friend from acting class, Mr. Molinaro was introduced to her brother, the producer Garry Marshall, who hired him for “The Odd Couple” and later for “Happy Days.”

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“Mork & Mindy,” the ABC sitcom that made Mr. Williams a star, began as “My Favorite Orkan,” an episode in Season 5 of “Happy Days.” In it, Richie and the Fonz do cosmic battle with Mork, an alien who turns up in Milwaukee itching for a fight.

The episode had “the worst script in the history of ‘Happy Days,’ ” Anson Williams, who played Potsie on the show, later recalled in a television interview. Shortly before the shoot, the actor originally hired to play Mork quit in disgust.

A frantic Mr. Marshall beseeched the cast: “Does anyone know anybody funny?” Mr. Molinaro, who was taking an improv class from the character actor Harvey Lembeck (best known as Cpl. Rocco Barbella on “The Phil Silvers Show”), put up his hand.

He had a classmate, he said prophetically, a young stand-up comic named Robin Williams.

With its new guest star, “My Favorite Orkan” proved so blazingly successful that the network created “Mork & Mindy.” The show was an immediate hit and ran from 1978 to 1982.

After “Happy Days” ended, Mr. Molinaro and Anson Williams were partners in Big Al’s, a chain of diners in the Midwest modeled on the one in the show.

Mr. Molinaro came out of retirement to appear in “The Family Man,” a sitcom shown on CBS in the 1990-91 season, playing a bumbling man who helps his newly widowed son-in-law (Gregory Harrison) raise four children.

Mr. Molinaro’s survivors include his son; his second wife, Betty Molinaro; and three grandchildren.

If Mr. Molinaro’s success in television did not give him a corresponding career in feature films — even those on which Mr. Marshall, his longtime champion, served as executive producer — there was a reason.

“I can’t work in movies with Garry because I’m so square that I won’t be in a movie that has four-letter words in it,” Mr. Molinaro told The Chicago Tribune in 1990. “That puts me pretty much totally out of films these days. Garry had a part for me in the first movie he made” — the 1982 comedy “Young Doctors in Love” — “but I started reading the scene ... and I stopped.

“He said, ‘You can’t do it, can you?’ ” Mr. Molinaro continued.

“I told him, ‘I don’t want to do a movie that I couldn’t watch with my mother if she were still alive.’ ”

Liam Stack contributed reporting.

A version of this article appears in print on October 31, 2015, on Page D8 of the New York edition with the headline: Al Molinaro, Diner Owner on ‘Happy Days,’ Dies at 96. Order Reprints|Today's Paper|Subscribe